PHP编程实现计算抽奖概率算法完整实例

<?php //计算抽奖的概率 function get_rand($proArr) {  $result = '';  $proSum = array_sum($proArr);  foreach ($proArr as $key => $proCur) {   $randNum = mt_rand(1, $proSum);   if ($randNum <= $proCur) {    $result = $key;    break;   } else {    $proSum -= $proCur;   }  }  unset ($proArr);  return $result; } $prize_arr = array(  '0' => array('id'=>1,'prize'=>'家电','v'=>2),  '1' => array('id'=>2,'prize'=>'数码相机','v'=>5),  '2' => array('id'=>3,'prize'=>'iPad','v'=>13),  '3' => array('id'=>4,'prize'=>'LED显示器','v'=>15),  '4' => array('id'=>5,'prize'=>'U盘','v'=>25),  '5' => array('id'=>6,'prize'=>'键盘','v'=>30),  '6' => array('id'=>7,'prize'=>'鼠标垫','v'=>10), ); foreach ($prize_arr as $key => $val) {  $arr[$val['id']] = $val['v']; } $rid = get_rand($arr); $res['yes'] = $prize_arr[$rid-1]['prize']; unset($prize_arr[$rid-1]); shuffle($prize_arr); $prize_arrcount = count($prize_arr); for($i=0;$i<$prize_arrcount;$i++){  $pr[] = $prize_arr[$i]['prize']; } $res['no'] = $pr; //抽奖结果 $ro = $res['yes']; print_r($ro);?>

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